Electromagnetically operated switch construction

ABSTRACT

A contactor construction which will permit easy access to the movable and stationary contacts and replacement of the magnet coil of the contactor while the contactor is wired on a panel. The construction includes a readily detachable cover which resiliently positions the coil so the coil may be lifted from its position on a stationary magnet when the cover is removed and absorbs shock generated when resilient pads carried on the armature engage the cover when the contactor is deenergized.

United States Patent Stallman et al.

[ Feb. 15,1972

[54] ELECTROMAGNETICALLY OPERATED 3,388,353 6/1968 lsler ..335/l32 SWITCH CONSTRUCTION 3,553,615 1/1971 Turnbill ..335/ 132 [72] Inventors: James E. Stallman, Whitefish Bay; James Primary Examiner Harold Broome J. Schlitt; Jordan F. Puetz; Don J. Ar- Attorney-Harold J. Rathbun and William H. Schmeling neberg, all of Milwaukee, all of Wis.

[73] Assi nee: uare D Company, Park Rid e, Ill.

g sq g [57] ABSTRACT [22] Filed: Dec. 18, 1970 A contactor construction which will permit easy access to the PP N05 99,573 movable and stationary contacts and replacement of the magnet coil of the contactor while the contactor is wired on a panel. The construction includes a readily detachable cover 8|. ..335/l32 which resiliently positions the coil so the coil may be lifted from its position on a stationary magnet when the cover is [58] Field otSeai-ch ..335/l32, 193, 202 removed and absorbs shock generated when resilient pads can ried on the armature engage the cover when the contactor is [56] References Cited energized.

UNITED STATES PATENTS p 7 10 Claims, 3 Drawing Figures 3,354,415 11/1967 Gribble et al ..335/l32 I42 I52 I62 I28 7 46 I26 I82 I24. i 22 174 Q: '20 I04 I30 76 I ll 08 2 i? .96 I 56 4 8 6 7o '60 54 n2 "2 l8 se- 52 34 52 72 62 I 9 59 I84 49 47 I88 4| 4| use \\\r\\\\ m 30 *36 38 L 2 37 PATENT EDFEB 15 I972 SHEET 1 OF 2 INVENTOR.

N A Z% MTTE L E L U A P TC N SSFR SS EE MM AA JJJD PAIENTEUFEB 15 m2 7 3,543,187

SHEET 2 OF 2 v42 52 I62 I a 46 26 l 2 2s 4 'I2 22 I74 I20 I04 I I06 no 96 NVEP TOR JAMES ESTALLMAN JAMES J. SCHLITT F I G 3 fgfu fi'f A w E s s R e ELECTROMAGNETICALLY OPERATED SWITCH CONSTRUCTION The present invention relates to electromagnetically operated switching devices, and more particularly to a device structure which is arranged so a cover portion of the device resiliently positions a magnet coil in the device and absorbs shock generated within the device when an armature in the device moves to a deactivated position.

Electromagnetic switching devices, of the type with which the present invention is concerned, are commonly known as contactors and are furnished as switching units of various sizes, having ratings which are normally in accordance with the standards promulgated by the National Electrical Manufacturers Association, commonly known as NEMA. Among the commercial requirements which a contactor is required to satisfy are that the contactor must be constructed so it can be easily mounted and wired on a panel and that the parts of the contactor be arranged so it is easy to inspect and replace the various components, such as the switching contacts and coil of the contactor while the contactor is wired on the panel.

ln larger sized contactors, i.e., NEMA Size 5 contactors which are rated to carry 300 amperes or less, a magnet of considerable size and weight is required to exert the force required to cause a proper engagement between the movable and the stationary contacts of the contactor. Thus from a design standpoint, the relatively heavy magnet in the contactor should be located as close as possible to the panel. However, present commercial requirements dictate that the most desirable form of a contactor should have its line or supply .wire connections at the top of the device and the load wire connections at the bottom of the device to provide an arrangement which is commonly termed as straight-thru wiring. Further, the commercial requirements dictatethat the wire connecting terminals be freely accessible and located as close to the panel as electrical clearance requirements will permit. Thus, if a contactor is to have a simple economical construction, a minimum size for its rated capacity and'is to include a straight-thru wiring feature, the design requirements dictate that it is impractical to mount the magnet portion of the contact directly on the panel. Therefore, in the device according to the present invention, the magnet is carried forwardly of the base which supports the stationary contacts and wire connecting terminals so that the device may be readily wired on the panel with straight-thru wiring and may be readily wired disassembled to permit the movable and the stationary contacts to be serviced. Further, in the contactor according to the present invention, the magnet armature is arranged to move toward the base when the electromagnet is energized to provide an economical simplified contactor structure. As the contactor construction herein described is intended for the larger size NEMA rated devices, it necessarily includes a relatively heavy armature which generates a considerable impact shock when the electromagnet is energized. The undesirable effects of the impact shock are minimized by a structure which includes a shock plate which supports the electromagnet and is mounted on four sturdy posts that extend from the molded base of the contactor. The four posts have inserts molded therein which extend to the mounting panel so that the shock accompanying the engagement between the armature and stationary magnet part is directly transmitted to the mounting panel and in efi'ect bypasses the base. Further, a molded barrier which encloses the contacts so as to isolate the poles of the contactor from each other and ground is suspended from the shock plate so as to be out of engagement with the base. Thus the shock is not transmitted through the barrier to the base and the inspection and servicing of the contact structure is readily accomplished by merely removing the screws securing the shock plate to the posts so that the entire assembly, including the electromagnet and barrier, may be removed to make the contacts of the structure readily accessible. The structure for mounting the electromagnet on the shock plate includes a pair of members which are secured to each other and to fingers that extend from the forward surface of the shock plate. The pair of members provide a rectangular frame that surrounds the stationary magnet and provide an arrangement whereby ,the coil may be readily removed for replacement purposes. The members further provide a guide for the armature and a structure for resiliently supporting the stationary magnet so the magnet has a limited movement on the shock plate to reduce the noise when pole faces of the armature and magnet are in engagement with each other and the shock which accompanies the impact between the armature and the stationary magnet when the electromagnet is initially energized.

The shock which is generated within the contactor when the armature moves to its deactivated position when the magnet coil is deenergized is absorbed by resilient pads on the armature which engage a cover for the contactor, The cover has resilient supports which position the coil on the shock plate and is removable to provide access to the coil for inspection and replacement purposes.

It is an object of the present invention to provide an electromagnetically operated switch that is easy to wire and service and includes a metal cover which is arranged to absorb the shock accompanying the movement of an armature within switch to a deactivated position and which includes resilient plungers which position a coil within the switch structure so the coil may be easily replaced when the cover is removed.

An additional object is to provide a cover in an electromagnetically operated switch structure which, when attached to the structure, positions a magnet coil within the structure and absorbs the shock accompanying the movement of an armature within the structure to a deactivated position and when removed from the structure provides an easy access to the magnet coil.

A further object is to provide an electromagnetically operated switch that is easy to wire and service and includes a metal shock plate which is mounted on four posts extending from an insulating base of the switch and provides a resilient support for an electromagnet assembly so the shock accompanying the energization of the electromagnet assembly is directly transmitted to a metal panel on which the base is mounted and a cover, which is secured on an insulating barrier which is mounted on the shock plate and cooperates with the base to provide compartments wherein the movable contacts and the stationary contacts are enclosed, that provides a means for resiliently positioning'the coil on the shock plate and absorbing the shock generated when the electromagnet is deenergized. The shock plate and cover are attached to the base and barrier to make the contacts of the switch fully accessible when the shock plate is detached from the base and the coil fully accessible when the cover is detached from the barrier.

Further objects and features of the invention will be readily apparent to those skilled in the art from the specification and appended drawings illustrating certain preferred embodiments in which:

FIG. 1 is a partly exploded view showing in perspective an electromagnetically operated switching device that incorporates the features according to the present invention.

FIG. 2 is a top end view of the assembled device in FIG. I with portions broken away to illustrate the mounting for an electromagnet assembly within the device.

FIG. 3 is a cross-sectional view of the assembled switching device that incorporates the features according to the present invention.

For the convenience .in description, the electromagnet switch or contactor is described herein as disposed in a horizontal position when the contactor is mounted on a front wall of a vertical panel, the parts of the contactor being described in relation to this position. Accordingly, the terms front and rear,-upper and lower, vertical and horizontal and the like are not absolute but merely define more readily the relative positions of portions of the parts and their relative positions to each other when the contactor is mounted on a panel.

Referring to the drawings, an electromagnetic switch asare stacked one upon the other. The components of the assembly include a metal mounting plate 12, an insulating base 14, an insulating barrier 16, a shock plate 18, an electromagnetic assembly 20, a cover 22 and a movable contact carrier 24.

As disclosed in an application for U.S. Pat. having a Ser. No. 99613, concurrently filed herewith, the contactor structure is arranged so that the shock plate 18 rests on four posts which extend forwardly of the base 14. The shock plate 18 mounts the barrier 16 in spaced relation to the base 14 to provide easy access to the movable and stationary contact structures of the device and transmits the magnet closing shock directly through the four posts to the mounting plate 12. Similarly, the details of the arrangement for connecting the armature of the electromagnetic assembly to the contact carrier 24 are shown in an application for U.S. Pat., Ser. No. 99574, which is concurrently filed herewith.

As shown in FIGS. 1 and 2, the metal mounting plate is formed as a stamped metal part to provide a means to secure the switch assembly 10to a vertical panel and the like, not shown. When the plate 12 is secured to the panel, an edge 26 becomes the bottom edge of the plate 12 and a surface 28 the front surface of the plate 12. Theplate 12 has a pair of rearwardly extending indentations 30 along its bottom edge 26 that provide a pair of spaced mounting feet having openings therein. The plate 12 also has an indentation 31 at its top edge which provides an elongated mounting foot having an opening therein which, together with the indentations 30, are provided for the purpose of securing the plate 12 to a vertical panel.

'The switch 10, as shown in FIG. 1, is a three-pole device in that it is capable of completing and interrupting a three-phase circuit when the switch 10 is actuated and deactuated. To enable the switch 10 to function as a three-pole device, the base 14 and the barrier 16 are formed of a molded insulated material having arc suppressing capabilities and cooperate with each other to provide three compartments which extend parallel between a top 32 and a bottom 34 of the switch 10. Positioned in each compartment is a set of stationary contacts and a movable contact in a manner disclosed in an application for U.S. Pat, Ser. No. 99612, concurrently filed herewith. Extending into the material of the base forwardly of a rear surface 36 and through the sidewalls of the base 14 is a slot 38. The slot 38 is centered on a centerline equidistant between the top wall 32 and the bottom wall 34 of the base 14 and is exposed to each of the compartments by a passage 39. Positioned on opposite sides of the centerline of the base in each of the compartments is a pair of stationary contact assemblies 41 which are respectively connected to terminal members 40. The terminal members 40 are arranged to accept the bared end of a wire conductor and are electrically connected to the stationary contacts within the compartment. The movable contact carrier 24 is generally U-shaped, having a bright 42 or body portion received in the bight 38, and a pair of arm portions 44 extending externally of the sidewalls of the base 14 and barrier 16. The arm portions 44 are connected to an armature 46 of the electromagnetic assembly and are moved rearwardly toward the plate 12 when the electromagnet assembly 20 is energized. At least one pair of compression springs 48 positioned between a rear wall of the bight portion 42 and the plate 12 cause the moveabie contact carrier 24 to be positioned forwardly when the electromagnetic assembly 20 is deenergized. Extending from the bight portion of the contact carrier 24 into each of the compartments is a projection 47 which provides a mounting surface for a movable contact 49 and the spring biased releasable retainer 51 for the movable contact 49 which engages the stationary contacts 41 in a manner fully disclosed in the application for U.S. Pat., Ser. No. 99612, supra.

Extending forwardly from a front surface on the base 14 are four spaced posts 50 each of which has a front surface 52 that is spaced from the remaining front surface portions of the base 14. The posts 50, which are more clearly described in the application for U.S. Pat., Ser. No. 996l3, supra. have metal inserts embedded therein that have a rear end flush with a rear surface 36 of the base 14 and extend substantially throughout the molded material of the posts 50. The inserts have threaded bores at their opposite ends which are respectively used to mount the base 14 on the metal mounting plate 12 and receive screws 54 at their forward end which mount the shock plate 18 on the front surfaces 52.

The shock plate 18 is formed as a metal plate having a thickness so it will resist deformation when it is mounted on the surfaces 52 provided by the four spaced posts 50. The posts 50 extend from the front surface of the base 12 so two of the posts 50 are on each side of a plane that is normal to the rear surface 36 and passes through the horizontal center of the base 14. The shock plate 18 has a front surface 56 and a rear surface 58 and four openings located therein to be aligned with the threaded bores in the four posts 50 when the rear surface 58 ispositioned on the front surfaces 52. The shock plate 18 is mounted on the front surface 52 in spaced relationto the front surface of the base by the four screws 54 which pass through the openings in the shock plate 18 and are threaded into the inserts in the posts 50. The shock plate 18 has an additional four spaced openings which receive four screws 60 to mount the barrier 16 on the rear surface 58. The barrier 16 has suitable inserts molded therein to receive the screws 60 so as to be suspended on the shock plate 18 with all the portions of its rear surface in spaced relation to the front surface portions of the base 14. v v

The shock plate 18 has a rectangularly shaped centrally located depression extending in its front surface 56 which provides a mounting surface 62 that extends between the walls of the barrier 16. Extending downwardly and forwardly on the lower side of the mounting surface 62 are a pair of spaced fingers 64 each of which has a support surface 66 spaced forwardly of the front surface 56 and has a threaded opening therein. Similarly extending upwardly and forwardly from the upper side of the mounting surface 62 are a pair of spaced fingers 68, also having a support surface '70 with threaded openings therein. The support surfaces 66 and 70 are all equally spaced forwardly of the front surface 56. A pad 72 of suitable elastomeric material, such as Buna N rubber, is secured to the mounting surface 62 to have its front surface substantially flush with the front surface 56.

In addition to the armature 46, the electromagnet assembly includes a stationary magnet part 74 and a magnet coil 76. The stationary magnet 74 is E-shaped and formed of a stack of E-shaped laminated magnet iron pieces which are positioned between a pair of E-shaped nonmagnetic iron plates which are secured together by strategically located rivets to provide a unitary assembly in a manner well known to those skilled in the art. Themagnet 74 has a rear wall 78, a pair of sidewalls and 82, a pair of end walls 84 and 86 and is shaped to provide poles at its opposite ends having forwardly facing pole faces 88 and 90 thereon and a centerpole that is located centrally between the pole faces 88 and 90 which provides a centerpole face 92. The end walls 84 and 86 are respectively shaped to provide a projection, not shown, that presents forwardly facing support surfaces at the opposite ends of the magnet 74 whereon pads, not shown and formed of a suitable elastomeric material, such as Buna N rubber, are positioned.

A means for mounting the stationary magnet 74 on the elastomeric pad 72, positioning the magnet coil 76 on the stationary magnet 74 and guiding the armature 46 during its movements, includes a pair of members 94 and 96 which are fully disclosed in the application for U.S. Pat. Ser. No. 99614, supra. The members 94 and 96 are identical and are formed as a L-shaped metal part to have leg portions which are arranged to provide arectangular frame when the members 94 and 96 are secured to each other and to the support surfaces 66 and 70 by screws 98 which are threaded into the threaded openings in the support surfaces 66 and 70.

The frame provided by the members 94 and 96 is spaced forwardly of the shock plate and surrounds the magnet 74. The leg portions on the members 94 and 96 have a pair of projections thereon which engage the sidewalls 80 and 82 and portions of the end walls 84 and 86 to position the magnet 74 against movement in a direction'parallel to the mounting surface 62. When the members 94 and 96 are mounted on the fingers 64 and 68; a rear surface on the leg portions of the members 94 and 96 will be positioned against the forward facing surface on the elastomeric pads on the end walls 84 and 86 so the magnet 74 will be resiliently mounted against movement in a direction vertical to the mounting plate 12 by the elastomeric pads 72 and the elastomeric pads on the end walls 84 and 86. The legs of the members 94 and 96 each have a pair of openings, not shown, therein and a portion 100 that extends forwardly from the remaining portions of the members 94 and 96.

The magnet coil 76 is formed as an encapsulated molded body which has a coil winding embedded therein connected to input terminals 102 which are externally accessible on a front side 104 of the coil 76. The molded body forming the coil 76 has a! rear side 106 and a rectangularly shaped passage 108 extending between the rear side 016 and the 106 front side 104. The passage 108 is sized to receive the portion of the magnet 74 that provides the pole face 92. Additionally, the coil 76 has four mounting pads 110 located at the corners of a rectangle extending from its rear side 106. The pads 110 have projections 112 extending therefrom. The projections 112 have tapered ends and are located on the rear side 106 to be received in the openings in the members 94 and 96 to position the coil 76 against movement in a plane parallel to the mounting plate 12 while the pads 110 engaging the front surface of the members 94 and 96 position the coil against rearward movement in the switch 10. Thus the members 94 and 96 position the coil 76 against movement in any of three directions. The coil 76 is formed so as to surround the centerpole face 92 and be received in the spaces between the centerpole face 92 and the pole faces 88 and 90. w

The barrier 16 has four posts 114 at each of its four corners that extend forwardly of the shock plate 18. Each of the four posts 114 has a U-shaped metal part 116 positioned thereon and a threaded insert embedded therein that is aligned with an opening 118 that is located in a bight portion of each metal part 116. The metal parts 116 are located by the posts 114 so that each part 1 16 provides a guide surface 120 which are engaged by surface portions on the upper and lower sides of a pair of molded members 122 and 124 to guide the armature 46 and the movable contact carrier 24 during their movement in a manner disclosed in the application for US. Pat., Ser. No. 99574 supra.

The armature 46 includes a stack of laminated magnet iron pieces 126 which are positioned between a pair of nonmagnet metal parts 128. The laminated pieces 126 and the parts 128 are secured together by strategically located rivets 130 and are shaped to provide pole faces 132 and 134 which are aligned to engage the respective pole faces 88 and 90 and a centerpole face 136 which is aligned with the centerpole face 92 on the stationary magnet 74. Each of the metal parts 128 has an L-shaped cross section and is formed of relatively thick metal to have leg portions 138 and 140. The leg portions 138 form the side walls of the armature 46 and the leg portions 140 form the front side 142 of the armature 46. The parts 128 are longer than the pieces 126 and thereby provide portions 144 that extend outwardly from the ends 125 and 127 of the pieces 126. The molded members 122 and 124 each have a side that presents an arcuately shaped surface 146 and a portion 148 that is received between the portions of the legs 138 and 140 that form the portions 144. The members 122 and.l24 are secured to the portions 144 by suitable screws, not shown, which extend through suitable bores in the members 122 and 124 and are received in threaded openings 150 that are located in portions of the legs 140 that form the portions 144. When the members 122 and 124 are secured to the parts 128,

the arcuate surfaces 146 will be spaced from the ends and 127. The armature 46 also includes a pair of elastomeric members 142 which are positioned on the front side 142. The elastomeric members 152 are received between notched portions 154 in the leg positions and have a portion 156 positioned on the in the leg portions side of the pieces 126 and a portion 158 that is trapped between portions of the end walls of the pieces 126, the arcuate surface 146 and the portions 144. The members 152 each have a front surface 160 that is spaced forwardlyof the front side 142.

The cover 22 is formed from'a relatively thick metal piece to have a U-shaped channellike shape which provides a bight portion 162; a pair'of legs 164 and 166 extending from the bight portion, and flanges 168 and 170 which extend outwardly from the legs 164 which form the U-shaped channel. The flanges 168 and 170 each have openings at their opposite ends which receive screws 172 that are aligned to be passed through the openings 118 and be threaded into the inserts within the posts 114 to secure the cover to the front surfaces of the posts 1 14. Each of the flanges 168 and 170 has an opening therein which receives a stem portion of a plunger 174 that is biased by a spring 176. The plunger 174 extending from the flange 168 is shown in FIG. 1 and the plunger 174 extending from the flange 170 is shown in FIG. 2. The plungers 174 each have a headed portion 178 on one end and a groove which receives a C-shaped fastener v180 at its opposite end. The fasteners 180 are positioned to engage the front surfaces of the flanges 168 and 170 to maintain the plungers 174 captive in the openings in the flanges 168 and 170 when the springs 176 which surround the stem portions of the plungers 174 are positioned between the headed portions 178 and the rear surfaces of the flanges 168 and 170. The plungers 174 are located in the flanges 168 and 170 so the headed portions 178 respectively engage the portions of the front side 104 of the coil 76 on diagonally opposite sides of the passage 108. When the screws 172 are tightened in the inserts in the posts 114, the stem portions on the plungers 174 will move in the openings in the flanges 168 and 170 and cause the pads 110 to be maintained in their position on the members 94 and 96 so that the coil 76 is resiliently held against movement in a forward direction on the stationary magnet 74.

Upon energization of the magnet coil 76, the shock accompanying the engagement between the pole faces 132 and 134 with the pole faces 88 and 90 will be initially absorbed by the elastomeric pad 72 and then transmitted to the shock plate 18 which in effect is directly mounted on the mounting plate 12. Further, when the magnet coil 76 is initially energized, the stationary magnet 74 will tend to move toward the armature 46 while the armature 46 is being attracted toward the stationary magnet 74. The elastomeric pads which are positioned between the stationary magnet 74 and the members 94 and 96 permit a slight movement of the stationary magnet 74 toward the armature 46 to further dampen the shock and cause proper alignment between the engaging pole faces when the pole faces on the armature 46 engage the pole faces on the stationary magnet 74.

The springs 48 constantly urge the movable contact carrier 24 and the armature. 46 in a forward direction to an at rest position where the front surfaces 160 on the pair of elastomeric members 152 engage a rear surface 182 on the bight portion 162. When the coil 76 is deenergized, the armature 46 moves forwardly and the shock which accompanies the movement of the armature 46 to its at rest position is absorbed by the elastomeric pads or members 152 as the surfaces 150 on the pads 152 engage the surface 182. I

The switch 10 also includes a suitable arc suppressing means that includes a plurality of arc plates 184 which are secured to the barrier 16 and operate in a manner well known to those skilled in the art. Access to the stationary and movable contacts of the switch 10 is readily obtained by removing the four screws 54 nd the pair of screws 186 that secure the members 122 and-l24 to the ends of the arms 44 so that the assembly, including: the shock plate 18, the barrier 16, the

electromagnet assembly 20, as well as the cover 22, is removed as a unit from the base 14 while the movable contact carrier 24 remains assembled with the base 14. The removal of the shock plate 18 and the components attached thereto will expose the stationary contacts assemblies 41 as well as the movable contacts 49 for inspection. The replacement of the stationary contacts is readily accomplished by removing the screws 188 and the supports for the stationary contact surfaces and substituting new supports and replacing the screws 188. The replacement of the movable contacts is readily accomplished in a manner described in the application for U5. Pat. Ser. No. 99,612 supra. The cover 22 may be removed from the switch by loosening and removing the four screws 172 and the armature 46 may be detached from the arms 44 by removing the two screws 186. When the cover 22 and the armature 46 are removed, easy access to the coil is obtained and all that is required to replace the coil 76 is to merely lift the coil 76 from its position on the magnet 74 and insert a new coil in the position occupied by the replacement coil before the armature 46 and the cover 22 are replaced.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. in an electromagnetically operated switch, the combination comprising: an insulating base having a front surface, a rear surface, a pair of side walls, a slot extending in the rear surface through the side walls, said front surface having spaced openings therein extending to the slot, a plurality of stationary contacts mounted in pairs on opposite sides of the openings on the front surface, and at least one pair of posts extending forwardly of the front surface to provide support surfaces that are spaced forwardly of the front surface, a U- shaped movable contact carrier having a bight portion movable in the slot, portions extending from the bight portion through the openings providing movable contact support surface on the front surface side of the base, movable contacts on the support surfaces arranged to engage the stationary contacts and a pair of arms extending from opposite ends of the bight portion externally of the sidewalls of the base, and an assembly including a metal shock plate, an insulating barrier, an electromagnet assembly, and a cover, said shock plate having a rear surface mounted on the support surfaces provided by the posts for removably mounting the assembly on the base and a front surface providing a support for the electromagnet assembly, said insulating barrier having a front wall mounted on the rear surface of the shock plate, a rear side, a plurality of spaced walls extending from the front wall to the rear side cooperating with the front surface of the base to define a plurality of spaced compartments with each of the compartments having a pair of stationary and a movable contact therein and portions extending to provide support surfaces that extend in a plane that is spaced forwardly of the front surface of the shock plate, said electromagnet assembly having a stationary magnet, a magnet coil, a movable armature, means for mounting the stationary magnet on the front surface of the shock plate, positioning the coil on the stationary magnet so the stationary magnet and the coil are supported by the shock plate and guiding the armature in its movement along a plane normal to the front surface of the shock plate into engagement with the stationary magnet part when the coil is energized, and means attaching the armature to the arms of the movable contact carrier, said cover having portions removably attached to the support surfaces provided by the barrier for exposing the coil when the cover is detached from the barrier, means carried by the cover and engaging the front surface of the coil for resiliently positioning the coil on the shock plate when the cover is attached to the barrier, and portions engaged by the armature when the cover is attached to the barrier and the magnet coil is deenergized.

2. The combination as recited in claim 1 wherein the means carried by the cover includes a pair of spring biased plungers.

3. The combination as recited in claim 1 wherein a front side of the armature has a pair of elastomeric members attached thereto which are arranged to engage the cover to reduce the shock when the coil is deenergize and the armature moves into engagement with the cover.

4. The combination as recited in claim 3 wherein the means carried by the cover includes a pair of spring-biased plungers.

5. The combination as recited in claim I wherein the cover is channellike in shape and has outwardly extending flanges extending from a pair of arms of a U-shaped channel portion.

6. The combination as recited in claim 1 wherein all portions of the rear side of the barrier are spaced from the front side of the base.

7. The combination as recited in claim 6 wherein the means for mounting the stationary magnet on the shock plate includes elastomeric pads which resiliently resist movement of the stationary magnet in two directions.

8. The combination as recited in claim 1 wherein the support surfaces on the barrier are provided by spaced posts that extend from the front wall of the barrier forwardly of the front surface of the shock plate and wherein the posts on the barrier have threaded inserts therein which receive screws for attaching the cover to the barrier.

9. The combination as recited in claim 1 including at least one pair of springs each having an end engaging the bight portion of the movable contact carrier to provide a force for causing the armature to engage the cover.

10. The combination as recited in claim 9 wherein the means carried by the cover includes a pair of spring-biased plungers.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION ,Patent NO. 3,643,187 Dated February 15, 1972 James E., Stallman et a1. Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 46, cancel "wired" and show marked lines 46 and 47 reading; panel with straight-thru wiring and may be readily disassembled to permit the movable and stationary contacts to Column 3, line 55, cancel "bright" and insert bight line 56, cancel "bight" and insert slot Column 5, line 23, cancel "016" and insert 106 same line, after "the", second occurrence, cancel "106". Column 6, line 3, "142", first occurrence, should read 152 line 5,

cancel "positions" and insert portions line 6, cancel "in the leg portions" and insert front line 66, cancel "150" and insert 160 line 73, cancel "nd" and insert and Signed and sealed this 12th day of September 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents ='ORM PO-105O (10-69) USCOMM'DC 603766 69 LL54 GOVERNMENT PRINTING OFFICE Z [96$ 0-356-334,

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION ,Patent NO. 3,643,187 Dated February 15, 1972 James E.. Stallman et a1. Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1; line 46, cancel "wired" and show marked lines 46 and 47 reading; panel with straight-thru wiring and may be readily disassembled to permit the movable and stationary contacts to Column 3, line 55, cancel "bright" and insert bight line 56, cancel "bight" and insert slot Column 5, line 23, cancel "016" and insert 106 same line, after "the", second occurrence, cancel "106". Column 6, line 3, "142", first occurrence, should read 152 line S,

cancel "positions" and insert portions line 6, cancel "in the leg portions" and insert front line 66, cancel "150" and insert 160 line 73, cancel "nd" and insert and Signed and sealed this 12th day of September 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM P0-105O (10-69) USCOMM-DC 60376-P69 U.S. GOVERNMENT PRINTING OFFiCE: I969 0-366-33k 

1. In an electromagnetically operated switch, the combination comprising: an insulating base having a front surface, a rear surface, a pair of side walls, a slot extending in the rear surface through the side walls, said front surface having spaced openings therein extending to the slot, a plurality of stationary contacts mounted in pairs on opposite sides of the openings on the front surface, and at least one pair of posts extending forwardly of the front surface to provide support surfaces that are spaced forwardly of the front surface, a U-shaped movable contact carrier having a bight portion movable in the slot, portions extending from the bight portion through the openings providing movable contact support surface on the front surface side of the base, movable contacts on the support surfaces arranged to engage the stationary contacts and a pair of arms extending from opposite ends of the bight portion externally of the sidewalls of the base, and an assembly including a metal shock plate, an insulating barrier, an electromagnet assembly, and a cover, said shock plate having a rear surface mounted on the support surfaces provided by the posts for removably mounting the assembly on the base and a front surface providing a support for the electromagnet assembly, said insulating barrier having a front wall mounted on the rear surface of the shock plate, a rear side, a plurality of spaced walls extending from the front wall to the rear side cooperating with the front surface of the base to define a plurality of spaced compartments with each of the compartments having a pair of stationary and a movable contact therein and portions extending to provide support surfaces that extend in a plane that is spaced forwardly of the front surface of the shock plate, said electromagnet assembly having a stationary magnet, a magnet coil, a movable armature, means for mounting the stationary magnet on the front surface of the shock plate, positioning the coil on the stationary magnet so the stationary magnet and the coil are supported by the shock plate and guiding the armature in its movement along a plane normal to the front surface of the shock plate into engagement with the stationary magnet part when the coil is energized, and means attaching the armature to the arms of the movable contact carrier, said cover having portions removably attached to the support surfaces provided by the barrier for exposing the coil when the cover is detached from the barrier, means carried by the cover and engaging the front surface of the coil for resiliently positioning the coil on the shock plate when the cover is attached to the barrier, and portions engaged by the armature when the cover is attached to the barrier and the magnet coil is deenergized.
 2. The combination as recited in claim 1 wherein the means carried by the cover includes a pair of spring biased plungers.
 3. The combination as recited in claim 1 wherein a front side of the armature has a pair of elastomeric members attached thereto which are arranged to engage the cover to reduce the shock when the coil is deenergized and the armature moves into engagement with the cover.
 4. The combination as recited in claim 3 wherein the means carried by the cover includes a pair of spring-biased plungers.
 5. The combination as recited in claim 1 wherein the cover is channellike in shape and has outwardly extending flanges extending from a pair of arms of a U-shaped channel portion.
 6. The combination as recited in claim 1 wherein all portions of the rear side of the barrier are spaced from the front side of the base.
 7. The combination as recited in claim 6 wherein the means for mounting the stationary magnet on the shock plate includes elastomeric pads which resiliently resist movement of the stationary magnet in two directions.
 8. The combination as recited in claim 1 wherein the support surfaces on the barrier are provided by spaced posts that extend from the front wall of the barrier forwardly of the front surface of the shock plate and wherein the posts on the barrier have threaded inserts therein which receive screws for attachiNg the cover to the barrier.
 9. The combination as recited in claim 1 including at least one pair of springs each having an end engaging the bight portion of the movable contact carrier to provide a force for causing the armature to engage the cover.
 10. The combination as recited in claim 9 wherein the means carried by the cover includes a pair of spring-biased plungers. 